Measurement of air flow through tilted windows in an experimental setup representing a classroom

This paper compares a tracer gas and a heat balance method to calculate the air flow provided by single-sided ventilation. Carbon dioxide is used as a tracer gas. The goal is to calculate the air flow in transient conditions. Simulated pupil dummies in a full scale classroom test facility at the Fraunhofer Institute for Building Physics emit carbon dioxide and heat. Due to mass flow meters, the tracer gas emission is supposed to be better known than the heat emission. Thus, tracer gas measurement gives more accurate results when the concentration difference between inside and outside air is sufficient. When this difference becomes too small, heat balance calculation method might still be able to provide some information on the exchanged air flow.